Games exist in which each challenge for which a level of difficulty is set is prepared as a subject for play. As one example, a game system is per se known (for example, refer to Patent Document #1) that provides a music game in which musical pieces are utilized as challenges, and in which the timings of execution of play actions that are executed in correspondence to these musical pieces are evaluated. Apart from the above, Patent Document #2 in the Citation List is considered to have some connection with the present invention.